New research from SA Water in greenhouse gas emissions has been included in the United Nations global climate change policy, setting the guidelines for reporting nitrous oxide emissions at wastewater treatment plants around the world.
In partnership with the University of Queensland, the ground-breaking research applied a new research method at South Australia’s largest wastewater treatment plant at Bolivar by using floating hoods anchored on sludge pools to capture, monitor and better understand emissions in real time.
As part of the trial, optimisation of aeration profiles at one of Bolivar’s activated sludge plants led to a reduction in nitrous oxide emissions of 30 per cent, leading to other plant improvements and energy savings while demonstrating a way of using the research at similar wastewater facilities across the globe.
Created as the UN’s body for assessing climate change science, the Intergovernmental Panel on Climate Change (IPCC) – formed of 195 member countries – has included the research findings in refinements to guidelines on greenhouse gases, published in May 2019.
SA Water’s Lead Scientist Environment and Wastewater, Dr Ben van den Akker, said acknowledgement from the UN is a feather in the cap for science and water research in South Australia.
“Nitrous oxide is a by-product of biologically removing nitrogen from wastewater, which represents up to 50 per cent of total emissions from wastewater treatment plants, and we’ve put a substantial focus over the years on investigating how to reduce this output and positively impact our emissions footprint,” Dr van den Akker said.
“This allows us to accurately predict emissions at any of our locations at any time and helps to map emissions hot spots to better target optimisation and control measures.
“The end result of this project has provided the most comprehensive data set on nitrous oxide emissions for step fed activated sludge plants like we have at Bolivar, and there is no greater recognition of the importance of this work on climate change than from the IPCC.
“We can now say that we’ve positively impacted international climate change policy, which is a pretty cool thing for SA Water and South Australia.”
Nitrous oxide emissions at treatment plants are far greater than methane or emissions from electricity consumption and have an estimated global warming potential 310 times greater than carbon dioxide.
The research has since been scientifically validated and published in four academic publications, putting SA Water at the forefront of emissions research in the water industry.
“Tackling climate change is everyone’s responsibility, and it is vitally important that water and wastewater utilities work to reduce emissions in their operations without compromising on plant performance,” Dr van den Akker said.
Director of the University of Queensland’s Advanced Water Management Centre, Professor Zhiguo Yuan AM, said nitrous oxide levels are a worldwide issue.
“Combatting nitrous oxide remains a real problem facing water utilities globally, and this goes to show how improving a plant’s design and operation can make a real impact on reducing the emissions footprint,” Professor Yuan said.
“Our work together with SA Water on this project demonstrates the importance of researchers and industry partners collaborating to deliver real benefits to society.”